ML19262A210

Abnormal Occurrence 75-11:on 750417,during Reactor Protection Sys Surveillance Testing,High Flux Trip Point for All Four Channels Found at 109.5%.Caused by Misinterpretation of Procedure.Trip Points Reset

ML19262A210
Person / Time
Site:	Three Mile Island
Issue date:	04/18/1975
From:	Herbein J METROPOLITAN EDISON CO.
To:
Shared Package
ML19262A207	List: ML19262A206 ML19262A210
References
NUDOCS 7910260552
Download: ML19262A210 (1)

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METROPGLITAN ED1 SON CO*APANY sussiouavor aenent.resucunuriescou

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ST OFFLCE BOX 480 MfDDt_ETOWN.OENNSYt.VANIA 17C57 TEi.EPHONE 717-944-4041

- e April 18,1975 'C

-- u - o Mr. J.P. O'Re-fily, Director Directorate of Regulatory Operaticas (;s Region I , -

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fi31 Park Avenue oJ blj!D.j0h(S1_.i King of Prussia, Pa. 19406

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Operating License EPR-50 Docket E0-289 -

Subject:

Abnomal Occurrence No..A8 75-11

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Dear Mr. O'Reilly:

This telegram is to confirvi the telecon between t.ee Spessard Region I-URC, and J.G. Herbein (TMI Station Superintendent) at 0830 hours0.00961 days <br />0.231 hours <br />0.00137 weeks <br />3.15815e-4 months <br /> la April 197S, The following report is sub:nitted in accordance with paragraph 6.7.2.a.1 (page 6-11) of technical specifications.

On 17 April, while conducting Reactor Protection System Surveillance Testing, the High Flux Trip Poict for all four Channels was found to be set at 109.5L The trip points were irrmediately returned to a valus of 104.75%, which is r,ithin the Technical Specification limit of 105.5L Investigation set on 13 April.into the cause revealed that the teip points had been improperly At that time the trip points ware being raised frorn 5% to the norinal (104.75%) value for power operetion in preparation fo: a plant startup.

The trip points were set to the wrong value because of a misinterpretation of the procedure by the instrument man making the adjustment.

Corrective action to prevent reoccurrence will include necess5ry procedure technical revisions to clarify over pcwer trip set::cint adjustaent requirements. In additicn.

RPS be surveillance performed by twoprecedures men. will require that Reactor Protection System Surveillance the activities of the other man who will make voltage measurements an adjustments in accordance with the procedure.

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r J.G. hertein 4 22 IGH-kmr

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Station Superintendent

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